Funds are requested to purchase a high sensitivity amino acid analyzer (Beckman Model 6300) along with special application accessories for this instrument, including a flow through scintillation counter and programmable fraction collector. Acquisition of these instruments will expand the capabilities of our Protein Sequence Laboratory and alleviate serious problems of over-usage and excessive down-time encountered with our current analyzer (Dionex D-500). The instruments will be primarily committed to four research programs studying the structure and function of dihydrofolate reductase, polypeptide cytolysins and axonal neurotoxins, Na-K-ATPase, and human plasma apolipo-proteins. All of the above projects are currently funded.